I've used Drinkwell for years; I bought my first one when my Merlin was diagnosed with CRD in the (futile) hope that it would encourage him to drink more. That was in 2001; I'm still using that same fountain. I bought another one to use at my mountain cabin, and I think I have two stashed away (one in each house) in case of failure. In spite of this, Mordred has me trained to turn on the bathroom faucet so that he can drink from it. Used to be, he'd simply jump onto the vanity when I went in to shower; then he started sitting on the vanity (which is next to the door) so that he could reach out & grab me as I walked by. He's now taken my training to new heights: last week, while I was working in the kitchen, he came and meowed and meowed until I noticed him, asked him his problem - and he led me straight to the bathroom!

Anyway, I've had great luck with the Drinkwell; I've never tried the Petmate, so I can't speak to that. Whatever you get, I'm sure you'll find it reassuring to know that the water is kept fresher - although it's of major importance to keep the unit, especially the filter, clean.